Sometimes (ex. django templates section at setting.py), a function expects an absolute path, but it's more practical when developing to refer it to the current file position in our code base. The rel function does exactly that.

To rename a bunch of files from "*.foo" to "*.bar" (like windows' REN *.foo *.bar) in unix.
Looking at the solution, it is easy to adapt it to more powerful character substitutions on a 1 to 1 basis.
If you want to test what will be executed b...

Given an an associative list ((k1 . v1) (k2 . v2) ... (kn . vn)), with possibly equal values for ki, it returns another alist where all cells have distinct keys and where values originally associated to the same key have been grouped as a list in the...